Many modern businesses use two separate telecommunication networks for voice and for data. The costs associated with installing and maintaining two networks have induced some businesses to seek ways to integrate voice and data on a single telecommunication network infrastructure. As a result, the telecommunications industry has produced systems that integrate telephones and computers onto the same network. In such systems, telephones and computers share the same cabling infrastructure for transmitting voice data and computer data.
Advances in technology, though, continually increase the data rate capability of networks. The Ethernet network, which is a prevalent type of local area network (LAN), is an example. Devices (or nodes) connected to an Ethernet network communicate with each other using packets having a structured format. The packets include a destination address, a source address, and the data. Initially, the 10 Mbps Ethernet network was the basis for the IEEE 802.3 standard, but Ethernet has since evolved to support network data rates of 100 and 1,000 Mbps. While current implementations of integrated telecommunication systems can adequately support network data rates of an order of 10 Mbps, such systems cannot adequately provide equivalent functionality at network speeds of 100 Mbps and beyond. This is due, in part, to the use of hubs by current implementations of integrated telecommunication systems to forward Ethernet packets on the LAN. A hub is a network device that deposits Ethernet packets received on one communication path onto another communication path. Many communication paths can meet at a hub. Because a hub does not provide separate collision domains, the devices using these communication paths compete against each other for use of the hub. A collision domain is a segment of the LAN where a collision occurs when any two devices attempt to transmit packets simultaneously on that segment.
When a packet collision occurs on a segment, the devices sending the packets become alerted to the collision and "back off," that is, the sending devices wait a predetermined period of time before attempting to complete the transmission of the packets on that segment. The IEEE 802.3 standard specifies a back-off algorithm that each sending device must perform to be compliant with the standard when involved in a packet collision.
A problem, however, is that at high data rates (e.g., 100 Mbps data rates and beyond), a sending device can incorrectly deem a packet transmission to have been successful although that packet later encounters a collision after propagating through the network. Normally, at lower data rates (e.g., 10 Mbps), this collision causes the sending device to back-off on future attempts to transmit the packet. However, the high data rates enable the sending device to complete the packet transmission before the collision occurs or is detected. Further, the sending device may even have continued to transmit other packets on that network segment. At high data rates, the propagation delay incurred in the network can prevent the timely detection of collisions and render the operation of the integrated telecommunication system impracticable.